Process for dyeing polyurethane foam in nonaqueous dye bath

ABSTRACT

A composition of matter comprising polyurethane foams and articles foamed therefrom, having applied thereto an essentially water-insoluble dyestuff of the class known as spirit or solventsoluble dyestuffs; particularly those dyestuffs of this class which are formed by the reaction of water-soluble dyes which contain water-solubilizing sulfonic or carboxylic acid groups with water-insoluble amines which are free from such solubilizing groups. In addition to the amine-salt-type of spirit or solventsoluble dyestuffs, the metallized O,O&#39;&#39;-dihydroxy azo-type of spirit or solvent soluble-dyestuffs may be used. The invention is also concerned with a method for the production of dyed polyurethane foams which comprises applying to the polyurethane foam or article a solution of a water-insoluble, spirit or solvent-soluble dyestuff in a volatile organic solvent.

Unite Streclt States Patent [151 mus [451 ,linn.1,197

1 PROCESS FOR DYEING POLYURETHANE FOAM IN NONAQUEOUS DYE BATH [52] U.S. Cl ..8/4, 260/25 AK [51 lint. Cl.

[58] Field of Search [56] References Cited UNITED STATES PATENTS 2,384,001 9/1945 Wesson ..8/173 X 3,120,423 2/1964 Herschler et a1 ....8/172 X 3,337,289 8/1967 Manwaring l ..8/4 3,432,251 3/1969 Fisher 1.8/4

OTHER PUBLICATIONS Colour Index 2nd Ed. 1956, Vol.2 pp. 2815 and 2816, Publ. AATCC, Lowell, Mass. 7

Du Pont Dyes & Chem. Tech. Bulletin, Vol 18 (2) 1962, pp. 89- 93.

Primary Examiner-George F. Lesmes Assistant Examiner-T. .1. Herbert, Jr.

Attorney-George L. Tone, Walter C. Kehm and Samson B. Leavitt [57] ABSTRACT A composition of matter comprising polyurethane foams and articles foamed therefrom, having applied thereto an essentially water-insoluble dyestuff of the class known as spirit or solvent-soluble dyestufis; particularly those dyestuffs of this class which are formed by the reaction of water-soluble dyes which contain water-solubilizing sulfonic or carboxylic acid groups with water-insoluble amines which are free from such solubilizing groups In addition to the aminesalt-type of spirit or solvent-soluble dyestuffs, the metallized 0,0-dihydroxy azo-type of spirit or solvent soluble-dyestuffs may be used. The invention is also concerned with a method for the production of dyed polyurethane foams which comprises applying to the polyurethane foam or article a solution of a water-insoluble, spirit or solvent-soluble dyestuff in a volatile organic sol vent.

6 Claims, No Drawings PROCESS FOR DYEIING POLYURETHANE FOAM IN NONAQUEO US DYE BATH BACKGROUND OF THE INVENTION The class of polymers known as polyurethanes are well known in the art and are commonly produced by reacting diisocyanates, such as toluene diisocyanate, with glycols, polyols, hydroxyl-rich polyesters and various polyethers. In the production of these polymers, several methods are available to produce foams by taking advantage of various aspects of the reaction. For example, if high acid values are present in the compound to be reacted with the isocyanate, a gas'forming reaction occurs which results in the production of a foam. It is also known to produce foams based on castor oil formulations as outlined in U.S. Pat. No. 2,787,601 or by the so-called one-shot" method wherein a glycol, a polyacid and a diisocyanate are reacted in the presence of an activator mixture to effect foaming.

Flexible foams formed by the methods outlined above are well known to be useful for filling and insulation purposes but in recent years have become useful in many other areas where color is an important characteristic. Thus polyurethane foams are now in common use in the production of clothing, cleaning brushes and sponges, cushions for weather stripping, lamination to fabrics to produce various materials such as synthetic leathers and the like. It has, therefore, become important to provide means for coloring the foams to enhance their appearance.

Various procedures have been attempted heretofore in an effort to devise suitable methods for dyeing polyurethanes in a satisfactory manner. One method which has been employed involves incorporating a pigment dye into the reaction mass prior to the production of the foam. However, this method has the disadvantage that the final coloration cannot be carefully controlled as it is dependent on reaction conditions. Moreover, it is difficult to obtain a uniform dispersion of the pigment in the reaction mass so as to obtain a uniformly colored product.

It has also been suggested to dye the polyurethane foams with direct dyes such as, for example, by the method described in U.S. Pat. No. 3,197,268. However, this method has not been entirely satisfactory because of the problem of obtaining suitable color fastness.

It is, therefore, apparent that a distinct need remains in the art for a suitable method of dyeing polyurethane foams and articles produced therefrom.

SUMMARY OF THE INVENTION It is accordingly one object of the present invention to provide compositions of matter comprising dyed polyurethane foams, and articles formed therefrom, and processes for dye ing the same, which overcome or otherwise mitigate the disadvantages of prior art methods of dyeing.

It is a further object of the invention to provide compositions of matter comprising dyed polyurethane foams, and articles produced therefrom, wherein the polyurethane foams are dyed with essentially waterinsoluble, spirit or solvent soluble dyestuffs dissolved in an organic solvent, the dyed products resulting therefrom being characterized by good fastness properties particularly in the bright colors.

A still further object of the present invention is to provide methods for the dyeing of polyurethane foams, whereby the final color of the foam is effectively controlled and which serves to mitigate or otherwise overcome the several problems faced by prior art processes.

Other objects and advantages of the present invention will become apparent as the description thereof proceeds.

In satisfaction of the foregoing objects and advantages, there is provided by this invention compositions of matter comprising polyurethane foams, and articles formed therefrom, having applied thereto essentially water-insoluble dyestuffs. Such spirit or solvent-soluble dyestuffs comprise (I) dyestuffs formed by the reaction of water-soluble dyes which contain water-solubilizing sulfonic or carboxylic acid groups, with amines which are free from such solubilizing groups, and (I1) spirit and solvent-soluble dyestuffs of the metallized, 0,0- dihydroxy-azo type. The novel dyed compositions of this invention are characterized by good color fastness and color uniformity.

There is also provided by the present invention a process for the production of dyed polyurethanes which comprises dissolving a water-insoluble, spirit or solvent-soluble dyestuff of the above types (I) or (II) in an organic solvent, and applying the resulting product to the polyurethane foam.

DESCRIPTION OF THE PREFERRED EMBODIMENTS It has now been discovered that certain essentially waterinsoluble, spirit or solvent-soluble dyestuffs may be employed to provide colored articles of the class of materials commonly referred to as polyurethane foams by dyeing, padding or printing the foams with organic solvent solutions of the dyestuffs to be described hereinafter. The resultant products have been found to be characterized by good fastness properties and uniformity of color. The process of this invention has been found extremely suitable where dyeing with bright colors is desired. Moreover, it has been found that the present invention provides a procedure wherein the final color of the foam may be easily and carefully controlled.

The polyurethane foams to which the invention is applicable are specifically set forth hereinabove. In general, it may be said that the products commonly referred to as polyurethane foams and the various articles produced therefrom, are susceptible to excellent dyeing employing the dyes and processes of this invention.

The dyes employed in the present invention in one embodiment generally comprise (I) water-insoluble, spirit-soluble amine salts of acid and direct dyes. These water-insoluble salts are generally spirit-soluble and are preferably produced by reacting a water-soluble dye molecule containing at least one sulfonic or carboxylic acid group with an equivalent amount of a water-insoluble amine. In a further embodiment, there may also be employed (II) metallized 0,0'-dihydroxy-azo'type spirit or solvent soluble dyes.

The amine-salt dyes may also be formed from metallized salts of water-soluble dyes which contain at least one sulfonic acid or carboxylic acid group which may be converted into the spirit-soluble salts. it is contemplated that any colored dye molecule which contains at least one acidic group of the class indicated may be employed to produce the water-soluble amine salt.

Among the acidic and direct dye molecules which have been found to be operable to react with the amine to form the amine salts are those of the following specific formulas, and Color Index name and number identification:

Acid Yellow 23; CI. 19140.

I ll N 0- III... (f zH5 021-15 H I ml! S 03H I NI].

I O C2115 HOaS N- S 03H HN- N- NH V Sulfonated copper phthalocyanine VI v IIIOZ -fifil HO-C N-Pfi CI OH S 01H I VII CH3 S 03H OH HO-C II N=N 1 5 Or C=O NO: I

VIII (|)II HO3S NHC 0-0 IX V... OH SOsH HOaS- SOsH Solvent, Orange 20.

Acid Blue 83; C.I. 42660.

Acid Blue 59; 0.1. 50315.

Direct Blue 86; (3.1. 74180.

Acid Orange 72; 6.1. 18740.

Acid Yellow 99; CI. 13900.

Direct Red 81; 0.1 28100.

Solvent Red 31; 0.1. 27306 Slllbellc dye Acid Yellow 36; Cl. 13065.

Direct Yellow 11; (3.1. 1000.

Sol-vent Red 49; C.I. 41517013.

In addition, any dyes of the anthraquinone, triphenylmethane and phthalein type are also considered operable in this aspect of the invention so long as they contain at least one acid group of the sulfonic or carboxylic acid type.

Each of the several dye molecules mentioned are well known in the art and particularly those indicated by the Color Index reference numbers listed hereinabove.

This listing of acid dye molecules is considered to be merely illustrative of the type of acid or direct dyes which may be employed in the invention and, therefore, is not to be considered as encompassing all operative dyes as it is contemplated that any acid or direct dyes containing sulfonic or carboxylic acid groups are operative in forming the dyestuff salts of the inventron.

To form the amine-salt dyestuffs of the invention, these acid group-containing dyes are reacted with an equivalent amount of a basic grouping comprising a water-insoluble amine to produce a water-insoluble dyestuff salt. It is contemplated that any water-insoluble amines may be employed in forming the dyestuffs of the invention. It has been found, however, that those described hereinafter are particularly suitable.

The salts of dyestuffs having acid groups formed by their reaction with organic bases are well known in the art as spiritsoluble dyes and are used for spirit printing inks, for ball point pen inks, for staining wood and leather, for coloring of lacquers and melt or solution coloring of certain plastics. See for example Lubs, The Chemistry of Synthetic Dyes and Pigments," ACS Monograph No. 127, Reinhold Publishing Corporation, N.Y. 1955, page 177.

It has now been discovered that these drestuff-salts are valuable for the dyeing of polyurethane foams when dissolved in a suitable organic solvent to form a dyebath. A number of such dyestuffs are commercially available under such trade names as AZOSOL, (General Aniline & Film Corporation); LUXOL, (E. I. du Pont); METl-IASOL, (Imperial Chemical Industries, Ltd); ORASOL, (Ciba, Ltd.); and ZAPON, (Badische Anilin Sodafabrik and Hoechst).

[t is particularly preferred to employ the salts of dyestuffs containing a sulfonic or carboxylic acid group reacted with cycloaliphatic amines, such as monocyclohexyl amine and dicyclohexyl amine, as described in U.S. Pat. Nos. 1,800,299 and 1,800,300 and 2,070,275 or with the disubstituted guanidines, particularly diaryl guanidines, exemplified by diphenylguanidine, described in U.S. Pat. No. 1,674,128 and alkylamines of the formula:

wherein R and R are alkyl groups of five to six carbon atoms and R" is selected from the group consisting of hydrogen and alkyl radicals of five to six carbon atoms, described in US. Pat. No. 2,095,077. Other amines which may be mentioned inelude long chain amines of the formula:

wherein R is a long carbon chain alkyl radical and R and R are alkyl radicals of one to two carbon atoms. Illustrative of this class of amines is diethyloctadecylamine, described in U.S. Pat. No. 1,836,047. Also found to be operative are the tertiary alkyl amines of the following formula:

wherein R is an alkyl radical of about nine to 15 carbon atoms and R and R are alkyl radicals of not more than about four carbon atoms. Exemplary of this class is n-dibutyllaurylarnine, as described in U.S. Pat. No. 1,836,048.

It is also known to use certain cationic dyestuffs, having secondary amino substituents, as the amine for forming the water insoluble, spirit soluble amine-salt-type dyestuff useful in this invention. As examplesof such cationic dyestuffs, whose salts with acid dyestuffs such as those named above may be used there may be mentioned the following:

Cationic Dyestuff Color Index Identification Rhodamine 66 CI. 45160 Rhodamine 8 CI. 45170 Rhoduline Blue 66 CI 42025 Rhodulinc Blue 513 C.l. 42140 Methylene Blue BB C.lv 52015 Other amine bases which may be mentioned include the imidazoles, e.g., 2-ortho-toluidobenzimidazole, described in U.S. Pat. No. 1,860,036, as well as acylated alkylamines, such as oleoyl ethanolamine, (U.S. Pat. No. 2,022,678); long chain alkyl amines including those derived from palm kernel oil and described in U.S. Pat. No. 2,187,816 and isoalkylamines, such as those illustrated in U.S. Pat. No. 2,315,870. In addition there may also be mentioned the alkylalkylolamines, such as N-di-n-butyl ethanol amine, described in U.S. Pat. No. 2,490,703. It is also contemplated that mixtures of these amines may be employed. For example, a mixture of diphenylguanidine and ditolylguanidine forms an especially preferred amine base reactant.

In addition to this listing of specific amine bases which are useful in forming the dyes of the invention, it is contemplated that other amines not listed are also operable and thus fall within the scope of the invention as other water-insoluble amine bases will become obvious to those: skilled in the art.

The acid or direct dye molecules described hereinabove are reacted with the amine bases in equivalent amounts to form the water-insoluble, spirit-soluble dyestuffs employed in the present invention.

In a preferred procedure for carrying out the reaction, the acid dye molecule is initially dissolved in an aqueous bath and the amine base added thereto. The amine per se may be added to the bath or it may be added in dispersed form or in the form of an acid salt. After addition of the amine, the amine salt of the acidic or direct dye precipitates as salt formation occurs.

wherein one X is hydrogen and the other X is nitro and Y and Z each represent hydrogen or a nonionic, nonchromophoric substituent such as chloro, bromo, lower alkyl, alkoxy, nitrilo,

trifluoromethyl and the like. Typical metals which may be employed to form the metallized dyes include cobalt, nickel, copper, chromium and the like.

Dyestuffs of this general type which may be employed include the following specific listing wherein the particular diazo base, coupler, metal and color of the resulting dye are set forth.

Diazo Basc Coupler Metal Color 2-Amino-4-nitrophcnol Resorcinol Co Red 2-Amino-4-chlorophenol Resorcinol Ni Brownish orange 2 Amino-4-chIoro-5-nitrophenol Acetoacetanilide Cu Bluish black 2-Amino-4-chlorophenol 4-tert.-butylphenol Cu Brown 2-Amino-4nitrophenol 3,4-Xylenol Cr Reddish brown Anthranilic acid 3-Hydroxy-2-naphthanilidc Cu Maroon 2-Amino5-chloro- 2-Hydroxy-3-naphth benzoic acid p-chloroanilide Cu Maroon 2,5-Dimcthoxyanilinc Z-Naphthol Cr Blue Dianisidine 3Hydroxy-Z-naphthanilidc Cr Greenish Blue Dianisidine 3-Hydroxy-2,5-dimethoxy-anilinc Cu Blue 2-Amino-4-chloro- S-Hydroxynaphthaphenol lencsull'onamidc Cu Bluish rubine 2-Amino-4-chloro- 4-Hydroxy-N,N- Snitrophcnol dimethyl-2,6-naphlhalenedisulfonamide Cr Greenish blue 3-Amino-4-hydroxy 4-Hydroxy-N-mehnn irlo 13' L L sulfonamide Cr Bluish red 2-Amino-4-melhyl B-Naphthylamine Co Red sulfonylphenol orange 4-Amino-3-hydroxy- B-Acetylamino- Co Rcddish benzencsulfonamide l-naphlhol blue Z-Amino-4-chloro-5- l-Acetylamino-B- nitrophonol hydroxy-N,N,N',

N'-tctramcthyl- 2,6-naphthalenedisulfonamide Cr Greenish blue 2-Amino-4-nitro- 3-Methyl-5-pyrazolphenol l-yl-bcnzene-J- sulfonamide Co Brownish yellow 2-Amino-5-sulfarnyll-(2,5-Dichlorobcnzoic acid phenyl)-3-methyl- S-pyrazolone Cr Reddish yellow 3-Amino-4-hydroxy- N,N-dimehtyl 3-Methyl-l-phenylbenzenesulfonamide S-pyrazolone Cr Orange In accordance with a preferred embodiment in conducting the process of the invention, the water-insoluble, spirit-soluble dye, obtained as set forth hereinabove, is applied to the polyurethane foam by use of a solvent system of the dyestuff. In a preferred aspect, about 0.1 to 5.0 percent of the dyestufi' is dissolved in a suitable solvent for application to the foam. Of the solvents considered suitable for the invention, organic solvents having a relatively low molecular weight are especially preferred. Representative of these preferred solvents are the following: methyl alcohol, ethyl alcohol, n-propanol; isopropanol, butanol, ethylene glycol, methoxyethanol, 2- ethoxy-ethanol, butoxyethanol, acetone, ethers and the like. It is also contemplated that other solvents such as carbon tetrachloride, chloroform, ethylene dichloride, benzene, toluene, and the like, may be employed in the process of the invention. The suitable solvents may be broadly described as alkanols, glycols, alkoxyalkanols, k'etones, ethers, hydrocarbons and halogenated hydrocarbons.

After formation of the dyestuff solution, a preferred method of carrying out the dyeing process is to pad the polyurethane foam with the dye solution, squeeze out the excess dye and dry the foam.

The following working examples are illustrative of the invention and are not intended to be limitative thereto.

Example I 0.5 Grams of the dicyclohexylamine salt of Dyestuff II (listed above) were dissolved in I00 grams of ethyl alcohol to form a dye solution. Then 5 grams of commercially available polyurethane foam was padded through this solution at room temperature and dried. The resulting uniformly dyed foam was a bright orange shade which exhibited good fastness to washing and dry cleaning.

EXAMPLE 2 The process of example 1 was repeated except that 0.5 grams of the dicyclohexylamine salt of Dyestuff ll (listed above) were dissolved in grams of 2-ethoxyethanol. The resulting dyed polyurethane foams was a bright orange shade which exhibited good fastness to washing and dry cleaning and showed uniform color.

EXAMPLE 3 0.25 Grams of the ditolyl guanidine salt of Dyestuff I (listed above) were dissolved in l00 grams of 2-ethoxyethanol to form a dye solution. Then 5 grams of polyurethane foam was padded through the solution at room temperature and dried. The resulting dyed polyurethane foam was a bright yellow shade which had good fastness to washing and dry cleaning and exhibited uniform color.

EXAMPLE 4 0.5 Grams of the salt formed by a 50:50 mixture of Rhodamine 66 (Cl. 45l60) and Rhodamine B (C.l. 45170) with Dyestuff Vll (listed above) were dissolved in 100 grams 2-ethoxyethanol to form a dye solution. Thereafter, 5 grams of polyurethane foam was padded through this solution at room temperature and dried. The resulting dyed foam was a bright red shade and exhibited very good fastness to washing and dry cleaning.

EXAMPLES 5 to 10 In the following examples, 0.5 grams of the dye indicated was dissolved in I00 grams of 2-ethoxyethanol to form the dye solution. Thereafter, 5 grams of the polyurethane foam was gadded through the solution as in example 1 and dried to yield right uniform colorations having good fastness properties. These examples are as follows:

Example Dye Color C.l. Name 5 Solvent Blue 9 Blue 6 Solvent Green 2 Green 7 Solvent Yellow 44 Yellow 8 Solvent Yellow l3 Yellow 9 Solvent Red 3i Scarlet l Solvent Blue 24 Blue EXAMPLES 1 l to 19 in the following examples 0.5 grams of the dye indicated was dissolved in 100 grams of 2-ethoxy ethanol to form the dye solution. Thereafter, grams of polyurethane foam was padded through the solution as in example i and dried to yield bright uniform coloration having good fastness properties. These examples are as follows:

amino)'2-anthraquinonesulfonic 2-naphthalencsull0nic acid.

It is obvious that numerous changes and modifications may be made in the invention without departing from the spirit thereof. Therefore it is to be understood that all such changes and modifications are considered to be included within the scope of the invention and the invention is not to be considered as limited except as set forth in the appended claims.

What is claimed is:

l. The process for dyeing polyurethane foam which comprises contacting such foam with a nonaqueous dyestuff solution of a. a water-insoluble, spirit or solvent-soluble amine-salt dyestuff formed by reaction of a dye molecule containing at least one carboxylic or sulfonic acid grouping with a water-insoluble amine, or

b. a water-insoluble, spirit or solvent-soluble metallized,

0,0-dihydroxy azo dyestufi dissolved in a low molecular weight anhydrous organic solvent therefor selected from the group consisting of alkanols, glycols, alkoxyalkanols, ketones, ethers, hydrocarbons and halogenated hydrocarbons and drying the dyed polyurethane foam.

2. The process according to claim ll wherein the dyestutf is acid selected from group (a).

is O 2-methylbenzimidazole. V ioict.

NH N cm S 0 11 F C 0 0 ll ill". C 11 l)icyclohmtylamino v (irecn.

3 j l S03 C S03 EXAMPLES 20 to 26 3. A process according to claim 11 wherein the dyestutf is present in the organic solvent in an amount of about 0.] to 5.0 percent per parts of organic solvent.

41. A process according to claim 1 wherein the dyestuff is selected from group (b).

5. A process according to claim 1 wherein the nonaqueous dyestuff solution is padded on the polyurethane foam.

6. A process according to claim ll wherein the organic solvent is Z-ethoxyethanol. 

2. The process according to claim 1 wherein the dyestuff is selected from group (a).
 3. A process according to claim 1 wherein the dyestuff is present in the organic solvent in an amount of about 0.1 to 5.0 percent per 100 parts of organic solvent.
 4. A process according to claim 1 wherein the dyestuff is selected from group (b).
 5. A process according to claim 1 wherein the nonaqueous dyestuff solution is padded on the polyurethane foam.
 6. A process according to claim 1 wherein the organic solvent is 2-ethoxyethanol. 